1. Field of the Invention
This invention generally relates to a technology for obtaining a tire information relating to a vehicle tire under a vehicle being running condition, and more particularly to a technology for obtaining an estimated tire information based on a vehicle wheel speed signal indicating a vehicle wheel speed which is represented by an angular rotational speed of a vehicle wheel installed with a tire.
2. Description of the Related Art
The tire information of a vehicle tire is important for an operator of a vehicle and a vehicle control device which controls the vehicle.
In a Japanese Patent Application Publication No. 2000-238516, a technology which relates to an obtaining the tire information by estimation based on a vehicle wheel speed signal indicating a vehicle wheel speed represented as an angular speed of a wheel installed with a tire. According to this disclosed technology, a tire pressure is estimated as a tire information based on the vehicle wheel speed signal and when the estimated tire pressure is below a normal value, the operator of the vehicle is informed that the tire pressure is abnormally low.
Further, the tire information important to the operator of the vehicle or the vehicle control device is obtained by other than the tire pressure. Such tire information includes a tire deformation related information which indicates whether a quick deformation is currently being generated or not, or whether such deformation may be possibly generated in near future or not.
However, a technology that can obtain the tire deformation information during the vehicle running has not been realized before.